The ERK/MAPK intracellular signal transduction cascade is activated by extracellular stimuli that play important roles in nervous system development and plasticity. Genetic disruption of ERK/MAPK signaling has been implicated in neurodevelopmental syndromes, yet our understanding of the functions of this pathway in the developing brain is rudimentary. This career development proposal seeks to define the precise role of ERK/MAPK in inhibitory neural circuits that are thought to be disrupted in neurodevelopmental syndromes. During the mentored phase, the precise functions of ERK/MAPK signaling in cortical inhibitory interneuron development will be established (Aim 1). Definitive mouse models for conditional gain and loss of ERK/MAPK signaling will be generated and studied with advanced imaging and electrophysiological techniques. Importantly, whether damaged inhibitory interneurons can be repaired following the normalization of aberrant ERK/MAPK activity in adult mice will be tested during both the mentored and independent phase (Aim 2). Finally, the global changes in gene expression that contribute to ERK/MAPK effects will be assessed specifically in inhibitory interneurons in vivo during the independent phase (Aim 3). These data will be essential for understanding the development and reversal of neural circuit defects in human syndromes resulting from mutations in ERK/MAPK signaling components. My long term goal is to obtain an academic position and study mechanisms of neural circuit dysfunction and restoration in neurodevelopmental disorders, particularly those linked to ERK/MAPK dysfunction. This line of research will require training in electrophysiology and cortical development. UNC is an outstanding institution to complete the mentored phase of this application, primarily due to the wealth of basic science and clinical researchers performing interdisciplinary research on numerous neurodevelopmental disorders. In addition to Dr. Snider's extensive experience and outstanding leadership, a number of exceptional scientists at UNC will provide electrophysiological training, formal class work, and scientific guidance. Relationships with outstanding researchers at other institutions have been established that will contribute to both phases of this proposal. Overall, the training experiences to be supported by this proposal will be critical for me to obtain a faculty appointment and establish an independent laboratory.